US9345083B2

Boost converter with a pulse frequency modulation mode for operating above an audible frequency

Summary by NHIP

Display boost converter control

The control circuit manages a display device boost converter to maintain switching frequencies above an audible threshold. A timing circuit detects pulses and outputs a supplemental signal if none occur within a cycle period corresponding to at least 20 kilohertz. When approaching this limit, the circuit activates a current sink to increase frequency, then deactivates it upon detecting the next pulse.

Claim Score by NHIP

Read claim 8, the broadest

Abstract

The embodiments discussed herein relate to systems, methods, and apparatus for executing a pulse frequency modulation (PFM) mode of a boost converter in order to ensure that a switching frequency of the boost converter is a above an audible frequency threshold. In this way, a user operating a display device that is controlled by the boost converter will not be disturbed by audible noises generated at the display device. The PFM mode enforces an audible frequency threshold by using control circuitry designed to increase or decrease the frequency of a pulse signal depending on how the frequency of the pulse signal changes over time. The control circuitry can apply an additional load to the boost converter in order to increase the frequency of the pulse signal when the frequency is approaching the audible frequency threshold.

US9345083B2, drawing sheet 1
Sheet 1 of 7

Term

8 yearsleft in the term

Expires 30 September 2034.

  1. Priority
  2. Filed
  3. Granted
  4. Today
  5. Expires

20 claims: 3 independent, 17 dependent

  1. 1
    A control circuit for a display device, the control circuit comprising:a boost circuit configured to output a switching signal to a subsystem of the display device based on a minimum frequency threshold;and a timing circuit configured to detect pulses in the switching signal, wherein, when the timing circuit does not detect a pulse in the switching signal before a cycle period of the timing circuit expires, the cycle period restarts and timing circuit causes the boost circuit to output a supplemental pulse to ensure that a frequency of the switching signal stays above the minimum frequency threshold.
  2. 8
    Broadest claimClaim Score 74, broad(NHIP)A machine-readable non-transitory storage medium storing instructions that, when executed by a processor included in a computing device, cause the computing device to carry out steps that include:generating a switching signal for a subsystem of a display device based on a minimum frequency threshold;and generating a supplemental pulse when a pulse is not detected in the switching signal during a cycle period, wherein the cycle period is reset when the pulse is generated and the cycle period corresponds to a frequency that is equal to or greater than the minimum frequency threshold.
  3. 15
    A computing device, comprising:a processor;and a display device, comprising: a boost circuit configured to output a switching signal to a subsystem of the display device based on a minimum frequency threshold;and a timing circuit configured to detect pulses in the switching signal during a cycle period, wherein, when the timing circuit does not detect a pulse in the switching signal before the cycle period expires, the cycle period restarts and the timing circuit causes the boost circuit to output a supplemental pulse into with the switching signal.